My new machine will be mITX, so no expansion room for a card. As of current, I basically don't use my headphones at all because switching is a pain the plugs are very snug and I imagine frequent switching will put unnecessary strain on the jacks. I have one 3.5mm to RCA cable that stays in the soundcard and goes to the T-amp or Asgard.
Right now, my computer has an HT Omega Striker soundcard with a T-amp for my Cambridge Audio S30 bookshelf speakers (+ BIC F12 sub) and a Schiit Asgard (original) for my Sennheiser HD580s. My current audio setup is a little less than ideal and I was hoping that could change with my new build.